Centrifuge



June 5, 1934. L, ALTPETER 1,962,048

CENTRIFUGE FledJlav 15, 1951 C m wlwy c a l ci A l i;

J0 f5 l J4 l f Patented June 5, 1934 irs!) STATES CENTRIFUGE Ludwig Altpeter, Essen, Germany Application May 15, 1931, Serial No. 537,739 In Great Britain May 19, 1930 3 Claims.

The invention relates to a further developinent of centrifuges with impervious walls pro"- vided with hollow members through which the water is removed which are inserted through the 5 wall of the drum and project into the material being centrifuged, as described and claimed in the specification of Patent No. 1,793,204.

In centrifuges having a cylindrical housing to the drum it is possible to dispose a plurality of the hollow members one above the other but if this is done a certain quantity of the solid material lying in the solid zone may become deposited in the spaces between thevindividual jets, partie ularly during the axial movements of a disc l5 rotating with the centrifuge for discharging the dry material. In this way the apertures and recesses in the hollow members become blocked to a large extent. It is true that these particles of solid material may be washed away with the water flowing off from the subsequent quantity of material to be centrifuged, but the particles are then lost and above all the outlet for the water from the subsequent charge is obstructed by this stoppage and the removal of water is incomplete. The orientation of the outflow oriilces for the water at an angle to the axis `of the centrifuge has been found by experience to be disadvantageous in the case of materials which comprise sticky or bituminous components. When removing water from these materials the outflow orifices and recesses are very readily and rapidly blocked and the passage of water from the centrifuge is thus prevented.

The present invention provides a suitable elongated or circular shape for the hollow members in cylindrical centrifuging drums, the elongated hollow bodies being divided longitudinally as required in which case individual discs or frames form gaps or slots for the passage of the clear water the breadth of the gaps being adjustable by means of projections or intermediate discs. The individual discs or frames may overlap in a manner of a roof or resembling venetian blinds whereby it is made impossible for the solid components of the material being vcentrifuged to emerge from the centrifuge with the clear water through the apertures for withdrawal of water and other disadvantages are also reliably avoided. The lateral walls of the hollow members may be smooth and interrupted only by the water withdrawal apertures between the individual discs. If the discs are arranged after the manner of a venetian blind then certain cavities or overlappings occur on the outer surfaces of the hollow members and solid material can collect therein. Owing to the direct force applied to this solid material by the centrifuge it is prevented from passing out through the water withdrawal apertures together with the clear water. They solid material which is constantly replaced con- 30 stitutes a suitable filter for the clear water. The clear water passes radially to the axis of the centrifuge or tangentially to the centrifuge housing through the apertures into the hollow members which are disposed on the inner periphery of the cylindrical housing. As the hollow members project into the material being centrifuged, water can pass into said members at every zone within the material. The apertures or orices in the hollow members are directed obliquely towards the interior of the hollow members. The interior of the member constitutes a cavity through which the clear water passes to the outside cf the centrifuge through apertures in the drum. The orifices and apertures in the water withdrawal jets may be directed radially to the axis of the centrifuge or normally to the lateral walls of the jet or at any other angle to the axis of the centrifuge. In order to permit of the passage of clear water from every zone in the material to be freed from water, the recesses or grooves on the cylindrical jets can be helical and in the case of elongated jets may have a corresponding inclination to the cylindrical housing or to the axis of the centrifuge.

In the description and arrangement of the water withdrawal members described above in the case of a centrifuge with a cylindrical drum the cross section of the water withdrawal apertures can be considerably increased as compared with the cross section when only circular water withdrawal jets are used and an unobstructed outlet for the clear water from the material to be freed from water is afforded at every level of the drum and in every zone within the solid material when using a small number of water withdrawal members on the inner periphery of the cylindrical drum. The elongated water withdrawal memberspassing through the centrifuge housing at approximately the height of the straight portion (water withdrawal Zone) are par-` ticularly suitable for material which it is difficult to free from water by centrifuging. In the case of material which is readily freed from water the circular form of the jets can be used which jets are preferably disposed at the level between the water removal zone and the dry Zone or are arranged one above the other in a plurality of rows.

The invention is illustrated in the drawing. 1 19 jay =by spacers c" provide diagonal lter slots c.

Fig. 1 shows a section through a cylindrical centrifuging drum provided at one end with parallel recesses or grooves in the hollow members by means of which water is withdrawn and at the other end with obliquely extending recesses or grooves.

Figs. 2 and 3 show portions of Fig. 1 on a larger scale and in longitudinal section.

Fig. 4 is a section along the line A-B of Fig. 3,

Fig. 5 shows on a larger scale and in cross section two plates of the embodiment according to Fig. 3,

Figs. 6 and 8 show a circular form of the hollow members through which water is removed and Fig. 7 shows a cross section through an elongated hollow member having a smooth outer surface.

These embodiments do not however represent the full extent of the possible constructions of the elongated or circular hollow members.

In the form of the invention as shown in Figures 2, 3, 4 and 5, each iilter body is built up from a number of rectangular rings or frames a each of which consists or" a pair of end bars 10 arranged in horizontal planes and a pair of lter bars 11 arranged in vertical planes. n the form shown in Figure 2, cross bars 12, corresponding to the end bars 10, connect the bars 11 intermediate their ends and this is advisable because of the length of the bars l1 in this form, whereas the short bars 11 of Figures 3 and 4 do not require such stiifening intermediate their ends. The rings or frames thus formed are spaced. slightly interposed between adjacent bars 10 and 12. A cover plate g is placed over the pile of frames and spacers and the whole is held together as a unit by bolts h. The end bars 10 adjacent the wall m of the centrifuge are provided with extensions i through which pass bolts 1c which serve to secure the unit to the wall m. Drain openings o are formed in the wall m so that fluid from the cell or cells thus formed in the unit may escape.

The shape of the filter bars 11 as used in this form of the invention is best shown in Figure 5. Each of these bars is provided on its outer side with a tongue or rib 14 disposed diagonally on the end bars 10, and these ribs are spaced to The diagonal outer surface of each rib continues to form the outer surface of the body of the bar 11 as at 15 while the diagonal inner surface of each rib meets the body surface 16 at an obtuse angle, this body surface 16 being parallel to the sides of the bar 10. Thus slits c are formed between the adjacent bars. The breadth of the passages which are enlarged inwardly to a cavity for leading off the liquid and have surfaces tapering towards the outside, is determined by insertions c" or lugs c' of variable thickness.

In the construction according to Fig. 6 the frames or discs a' abut directly against each other by means of lugs c of pyramidal form and water discharge gaps l expanding inwardly are left free between these lugs. The uniform separation of the frames or discs a from the retaining bolt h is maintained by means of intermediate members n constructed to permit the passage of the clear liquid.

In Fig. 7 the individual discs or frames a of the hollow member a are shown in the case of elongated jets with smooth parallel outer walls. ln this construction the dry material is prevented. from accumulating at the apertures through which the clear water flows. The dry material is heavier and denser than the clear liquid. In consequence of the considerable friction caused by the centrifugal forces generated, the dry material cannot pass out through the water withdrawal apertures into the jets, provided that it is not flocculent. The inwardly expanding apertures and orices in the hollow members preferably are inclined inwardly in order to facilitate the discharge of the water and for preventing stoppages.

What I claim is:

l. In a centrifuge having a revolving portion provided witi a side wall, a filter element consisting of a series of frames and a series of spacers, said frames and spacers being superposed in alternation, and means to hold said frames and spacers together to form a filtering unit, said unit being secured to the side wall, said frames each consisting of a pair of rectangular end members and a pair of side members, said spacers being located between the end members of adjacent iraines, said side members being arranged to forni slits narrow on the outside and wide internally.

2. 1n a centrifuge having a revolving portion provided wit side wall, a iilter element consisting of a series of frames and a series of spacers, said frames and spacers being superpcsed in alternation, and means to hold said frames and spacers together to form a filtering unit, said unit being secured to the side wall, said frames being spaced by the spacers to provide inlet slits at their sides and having their sides formed to provide slits narrow at the outside and wide internally to prevent clogging by the material ltered, the side walls of each slit being parallel for a dis tance from the outside of the rings inwardly and flaring from the inner end. or" the parallel portion.

3. In a centrifuge having a revolving portion provided with a side wall, a filter element consisting of a series of frames and a series or" spacers, said frames and spacers being superposed in alternation, and means to hold said frames and spacers together to form a iiltering unit, said unit being secured to the side wall, said frames each consisting of a pair of rectangular end members and a pair of side members, said spacers being located between the end members of adjacent frames, said side members being arranged to form slits narrow on the outside and wide internally, the side walls of each slit being parallel for a distance from the outside of the frames inwardly and flaring from the inner end of the parallel portion.

LUDWIG ALTPETER. 

